However, for odd values of n, it does not match GCD. So it's not simply a drawing of the GCD pattern.
And when n is even, there's also a heuristic argument that there are only finitely many counterexamples; i.e. you should expect to find the pattern from your process exactly match that from just the gcd, beyond a few counterexamples: https://news.ycombinator.com/item?id=17106648
Meaning that the chance of finding a prime in these sequences of N numbers approaches one, after eliminating the cases that make primes impossible (n odd and r=2 mod 4, gcd(r,c) > 1).
Is there any deeper meaning to that, or is it simply that the probability of finding a prime in any sequence of n numbers approaches one as n increases, excluding sequences in which primes are impossible?
See the Mathematica notebook, which correctly renders it for any value.
Https://GitHub.com/shaunxcode/a-pattern-in-the-primes